1. Field of the Invention
The present invention relates to an air bag system including an air bag which is adapted to inflate from a folded state resulting when accommodated by introducing an inflation gas thereinto and which is set to enable the suppression of an internal pressure produced when the air bag so inflates.
2. Related Art
In some of conventional air bag systems, a discharge port through which part of inflation gas can be discharged is formed in an air bag, so that an internal pressure produced when the air bag inflates is suppressed by controlling opening and closing of the discharge port by an opening and closing control unit according to a seated position and his or her build of an occupant seated in the seat (refer, for example, to U.S. Pat. No. 6,648,371).
In the conventional air bag system, however, a configuration has been adopted in which a discharge port of a substantially circular opening is provided in a circumferential wall which makes up the air bag, a flap material which is provided separately from the air bag and is of a size which can close the discharge port is securely sewn to a circumferential edge of the discharge port, and a tip end side of the flap material which is spaced away from the sewn portion is connected to an opening and closing control unit, whereby the discharge port is opened or closed by maintaining or canceling the connection with the flap material. Namely, since the conventional air bag system adopts the configuration in which the discharge port bored in the base sheet making up the air bag is made to be closed by the flap material from an outer circumferential side thereof, there has still been left room for improvement in an area where accurate opening and closing of the discharge port is realized while securing good sealing properties.